The present invention relates to a lowering position setting device for a tonearm. More particularly, the invention relates to a lowering position setting device for a tonearm for use in an automatic record turntable capable of automatically repeating the reproduction of music recorded on a record disc.
A very large variety of audio record turntables are known in the art. In one such turntable, when a start switch is activated to start the reproduction of music recorded on a record disc, the turntable tonearm automatically begins to move toward the center of record disc, that is, in the forward direction. Hence, the tonearm automatically moves toward the beginning of the record groove of the record disc. Then, the tonearm is lowered at a position depending on the size of the record disc to start the reproduction thereof. Subsequently, after the record is finished, the tonearm is first elevated then is returned toward the arm rest. When the tonearm arrives at a position above the arm rest, it is lowered onto the arm rest.
According to the above described operational steps, the reproduction operation is carried out. An automatic record turntable is also known which is capable not only of performing the above-described reproduction operations but also an automatic repeat operation in which the same record is automatically repeated.
With a conventional automatic record turntable capable of automatic repeat reproduction of recorded music, generally, at the end of each record, the tonearm has to be returned to the arm rest and then the initial operations of the tonearm are repeated in order to again lower the tonearm to the start position on the record disc. However, this mode of operation is disadvantageous in that the automatic repeat reproduction requires a relatively long period of time from the end of the first play of the record to the beginning of the repeat play. In order to eliminate the above-described drawbacks, an automatic turntable has been proposed which is equipped with a lowering position setting mechanism for the tonearm which is capable of lowering the tonearm to a desired position, the start position on the record disc, without returning the tonearm to the arm rest during the automatic repeat operation.
The above-mentioned tonearm lowering position setting mechanism includes an interlocking device which swings or slidably moves in association with the movement of the tonearm, an engaging device which engages with the interlocking device to thereby stop the swinging or sliding operation of the tonearm at a desired tonearm position, and a driving device which drives the interlocking device and engaging device so that they engage with each other in response to a predetermined signal. The engaging device is provided with protrusions each corresponding to the size of the commercially employed sizes of record discs such as 30 cm, 25 cm and 17 cm. The engaging device is driven by the driving device so that a designated protrusion engages with the interlocking device with predetermined timing during the lead-in operation of the tonearm. Under this condition, the interlocking means engaged swinging or slidably moving with the designated protrusion of the engaging means, the tonearm is stopped at the desired lowering position. In the above described tonearm lowering position setting mechanism, the driving operation of the engaging device by the driving device must be carried out taking the size of record disc into account during the lead-in or return operation of tonearm. Therefore, the timing for the driving operation is quite critical. If a lag in the timing occurs, the stopping position of the tonearm may deviate from the desired position.